Actually, more like 23 minutes and 37 seconds of gameplay. Also, a note about the below list. I didn't write it as I was watching like a smart person would so I could have missed some stuff. Still, you get the idea.
Things of interest:
-Completely open world.
-50 square kilometers
-No loading, it's all seamless.
-Dynamic day/night cycle
-Dynamic wind/weather cycles
-1 minute in real time is 5 minutes in game time
-There are 9 playable characters. Whichever characters you don't play with become NPCs and can help you on your mission.
-There are over 100 missions.
-Their first estimate was 50 hours of gameplay.
-Africa is dirty so your guns will jam.
-You can fix your vehicles so you don't get stranded
-There is a sort of weapon shop so you can pick what weapons you use for what mission.
-Some animations look a little stiff, but they still have time to change them before the game gets released.
-Intelligent roadside system (road signs telling you where to go). Presenter adds "But it's an open world so you do what the fuck you want."
-Fire. Freaking. Propagation.
"Louis-Pierre Pharand from Ubisoft showing for the first time in the world Far Cry 2, at DreamHack Summer 2008." read